1.2xyz(2x-6y+9z)
2.8a(b-a)
3.2x(x^2+4)(x+2)(x-2)
4.(a-1.5b)(a-0.3b)
5.(1/12)mn(2n+m)(2n-m)
6.3x(x-2)(x-2)
7.-(xy-6z)^2
8.2a(a+b)(a-b)
9.8abc(a+b-c)[3bc-4a-4b+4c+c^2]
10.(2y-3x)^2
11.(a-1)(a-1)(a+1)(a-3)
12.-3xy^2(x-1)(x-2)
13.(ab-c)^2
14.(y-7)(y+2)
15.(x+3)(x-3)(x^2+4)
16.(2x-5)(3y-2)
17.(1+y-x)(1+x-y)
18.(a-4b-2)(a-4b)
19.(a-2b)(a+2b-1)
20.(-1/3)(x+6y)(x-6y)